Cultivated land carrying capacity and population migration in ecological barrier zone of the Three Gorges Reservoir

An ecological barrier zone project in the Three Gorges Reservoir is an important follow-up of the Three Gorges Project for protecting water quality and ecological environment, reducing population pressure on the Three Gorges Reservoir environment. Nonetheless, numerous project building difficulties have been caused by excessive human activity and sharp contradictions between population and available land. It was imperative to transfer congested residential in the region in order to relieve ecological pressure. Relevant consideration was the ecological carrying capacities of current and post-aforestation of cultivated lands. Based on "status-quo" state analysis, this study calculated the existing carrying capacities of cultivated lands (CLCC) in 15 districts in Chongqing. The study area is along the Three Gorges Reservoir and both the area and yield of cultivated lands were analyzed through calculation of per cap. demand for cultivated land and grain. The study also forecasted the CLCC after afforestation construction. The result showed that population carrying capacity of cultivated lands in the study area was severely inadequate. Deficit in the "status-quo" carrying capacity of cultivated lands for area (CLCCa) was 117.01 million people and that in the carrying capacity of cultivated land for production (CLCCp) was 94.93 million people. Moreover, regional deficit in terms of the CLCCa in 2020 was 127.39 million people. It was necessary to enhance an ecological migration of people in the region based on congestion trend in CLCC. Rural population migration was required with the key emigration and immigration areas being the northeast and southeast regions, respectively, according to distributions of CLCC and population in the study area. Added to migration implementation, it was the enhancement of CLCC to maintain dynamic balance of the area, and enhance the quantity of cultivated land. This was good for economic development, social stability and ecological security in the study area.